Over the past several decades, the telecommunications industry has exploded, and the incorporation of optical fiber into this industry is revolutionizing the way information is transmitted. Communication systems which use optical fiber as the transmission media offer some significant advantages over traditional wire-based systems, such as higher bandwidths and transmission rates, lower transmission losses, lower implementation costs, and greater electrical isolation.
Optical components utilized in these optical fiber communications systems typically require an ability to operate over a wide range of power levels. Devices, such as optical attenuators, have been developed to control optical signal power attenuation. Several types of optical attenuators have been developed, but these systems and devices have several drawbacks.
For example, one system attempts to provide optical attenuator by varying the orientation between a pair of optical fibers. In this type of system, one fiber is maintained in a fixed position while the other fiber is mounted on a moveable surface so that its terminal end can be axially or angularly moved relative to the fixed fiber. In these types of systems, signal attenuation is described as being accomplished by moving one fiber relative to another, causing an imperfect transmission between the fibers.
Other systems utilize a variety of different types of signal blocking devices in an attempt to provide optical signal attenuation. One system, for example, describes an ability to provide signal attenuation by moving a light blocking member that is disposed between two optical fibers. These signal blocking systems include the utilization of optical shutters that are controlled by thermal actuators or other types of micro electromechanical systems (MEMS) devices.
Despite the problems inherent to the optical attenuators currently available, single mode (SM) fiber, with its virtually unlimited bandwidth, has slowly become the standard in the telecommunication industry. Since the diameter of the core in a SM fiber is approximately ten (10) microns, the optical attenuators which use crude drive mechanisms are incapable of precise signal attenuation.
In view of the foregoing, a present need exists for an optical attenuator that can provide optical signal attenuation over a full optical power range. Additional need exists for precise control over the optical attenuation, allowing for the transmitted optical power to be dynamically altered as may be required by a specific application.